Katy Perry backstage before her performance at the United Center August 7, 2014.

Katy Perry backstage before her performance at the United Center August 7, 2014. (Chris Sweda/ Chicago Tribune)

Katy Perry gave a backstage interview right before she performed at the United Center. Here's what she said:

Katy Perry discusses one of the first times she met a celebrity in LA and how that star treated her

Katy Perry wasn’t sure what to do in Chicago with her free time other than museums. She asked for suggestions backstage at the sold-out United Center as the crowd waited anxiously for the “Firework” singer to take the stage.

“Can you give me, like, a things-to-do list?” Perry said Thursday, the first of her back-to-back nights at the United Center. “If you get me a cheat sheet of what to do in Chicago, I will (do it).”

Either this is one of the few aspects of Perry’s life that doesn’t involve handlers and meticulous scheduling or Perry — who was decked out in the make-up and futuristic, glow-in-the-dark crop top and skirt she wore during her opening number — was simply making conversation.

I suggested the first idea that came to mind: Pizza.

OK, so it wasn’t the most creative recommendation. You try giving suggestions to a world-famous pop star on the spot and see how easy it is. And besides, everyone loves pizza — or so I thought.

“I mean, the print, yes,” said Perry when asked if she likes pizza. (Perry wore a one-piece, pizza-print swimsuit and matching earrings in her “This Is How We Do” music video.) “I mean, I don’t eat a whole lot of pizza, but I love how it looks.”

Perry has a knack for small talk with strangers and making them feel important. She perked up after hearing my Willis Tower Skydeck recommendation (“I love that. Let’s do that,” she said). Right before our interview, Perry met with nine teachers from Dawes Elementary School in Evanston on behalf of tour sponsor Staples and DonorsChoose.org. She interrupted the group photo to ask each what subject they teach and asked one of her handlers take a photo of one teacher in particular because she was a fan of the teacher’s eyeliner.

“I’m always drawing inspiration,” said Perry, likely making that teacher’s day, if not month.

As part of her partnership with DonorsChoose.org, she meets with teachers in different cities who have taken advantage of the website — sort of a Kickstarter for teachers in need of school supplies for their classrooms. Staples funded 227 Chicago-area requests on the site Thursday in honor of the Chicago tour stop.

“It’s a really easy way to send funds to classrooms that really need it,” said Perry, who pointed out that teachers spend over $400 of their own money each year on classroom supplies. "...It’s something that was important to me because I didn’t grow up, unfortunately, with a great education. It’s one thing, if I could go back, I would definitely shake my parents and say, ‘Put me in school, don’t take me out of school.’ I was home-schooled a lot. I was taken out during the semester sometimes because they were traveling ministers.”

Before she hit it big with “I Kissed A Girl” in 2008, Perry released a Christian album in 2001 under her real name, Katy Hudson. She moved to Los Angeles when she was 17 and had one of her first celeb encounters there, meeting No Doubt singer Gwen Stefani at a party through a mutual producer. The meeting left an impression on Perry.

“I met her and was, and still am, such a huge fan,” Perry said. “She was so kind to me and cool. I’ll never forget that and I’ll always kind of think of her in this kind of cool light because of that. There were other people I met that didn’t have the time for me and weren’t that great. You never know what’s actually going on in a person’s life. You don’t know what happened to them before you met them … and that’s why they are the way they are. But I do think about it whenever I get in contact with my fans. I know this may be the only time they’ll ever meet me. I try to take advantage of that moment and be kind and grateful.”

Perry said Thursday’s show was her 42nd on the Prismatic world tour, which kicked off in Northern Ireland in May and is scheduled to wrap in Sweden in March. The over-the-top production involves various costume and set changes — some cat-themed, some Egyptian-themed — and acrobatics that see Perry lifted off the ground by strings. There’s a reason a Staples representative prepared the teachers for the spectacle by telling them “This is a show, not a concert."

Does Perry find herself getting quirkier the older she gets or is she considering toning it down?

“Quirkier?” Perry asked. “What does quirky mean, exactly? I want the full definition.” I think quirky, in part, means interesting, to which she replied “Interesting or left of center? I think I am pretty much exactly how I’ve always been.”

Regardless of what you want to call it, it is working for her. Perry and Michael Jackson are the only artists to have five singles on one album reach No. 1 on the Billboard Hot 100. She also has the most Twitter followers in the world: 55 million, nearly two million more than runner-up Justin Bieber.

The pressure is on for Perry to deliver while on tour, given her current position in the industry. And while she seems to be up to the challenge, the tour can be demanding, she said. Perry and her dancers regularly take part in physical therapy and acupuncture (Perry said she had 20 needles in her neck earlier that day to alleviate neck pain). She believes the tour is probably “five times as hard” as her California Dreams tour and pointed out she is now three years older than she was back then.

“Those two things combined are definitely taking a toll on me,” Perry said, “but I’m trying to look after myself as much as possible.”

Asked to imagine what her show might be like in 10 years, Perry said she definitely could envision it sounding differently.

“I’m 29 and can only be 29 at this moment,” Perry said. “When I’m 39, I’m sure I’ll be doing things differently. But age is an attitude. I think you can have that youth sensibility forever if you decide to. There are different things that I want to do in the future: I want to do an acoustic record, I want to do a full dance record, I want to try different things. I want to experiment a lot more. We’ll see. I hope that I’m building a career for myself, not just a one-stop shop.”

During a quieter moment in Thursday’s show, Perry watered her “garden” on stage, and a Chicago style deep dish pizza from Giordano’s rose from beneath the stage (her Philadelphia show earlier in the week reportedly included a Philly cheesesteak). The pizza box featured a picture of Michael Jordan on it to further the Chicago theme.

Perry brought an ecstatic young girl from Wisconsin on stage to present her with the pizza. This part of the night, and the one in which she took selfies with audience members, allowed for a brief moment of spontaneity in an otherwise heavily staged show.